For the 300 million people worldwide who live with disabling hearing loss, few alternatives exist to restore their critical sense of hearing. Hearing aids. Cochlear implants. And little else.

Both alternatives are too expensive for most of the world's population to afford.

“Hearing aids cost about $5,000 every five years, and cochlear implants cost at least $50,000,” said Dr. Richard Kopke, an ear surgeon and CEO of Oklahoma City's Hough Ear Institute. “And 90 percent of those 300 million people cannot even afford a hearing aid.”